U.S. patent number 6,784,227 [Application Number 09/973,890] was granted by the patent office on 2004-08-31 for crosslinking base layer for fixing interlinings according to double dot and paste process.
This patent grant is currently assigned to Degussa AG. Invention is credited to Guenther Koehler, Ulrich Simon.
United States Patent |
6,784,227 |
Simon , et al. |
August 31, 2004 |
Crosslinking base layer for fixing interlinings according to double
dot and paste process
Abstract
A microencapsulated adhesive component, comprising a
cross-linking constituent microencapsulated with a silanized
polybutadiene, wherein the reactive constituent has been first
reacted in the melt with cross-linking, thereby resulting in a
cross-linkable hot-melt adhesive component for coating and/or
laminating surface formations.
Inventors: |
Simon; Ulrich (Herne,
DE), Koehler; Guenther (Marl, DE) |
Assignee: |
Degussa AG (Duesseldorf,
DE)
|
Family
ID: |
7659327 |
Appl.
No.: |
09/973,890 |
Filed: |
October 11, 2001 |
Foreign Application Priority Data
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Oct 11, 2000 [DE] |
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100 50 231 |
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Current U.S.
Class: |
523/211; 101/36;
525/375; 427/221; 524/837 |
Current CPC
Class: |
C08G
18/792 (20130101); C08G 18/603 (20130101); C09J
177/00 (20130101); D06N 7/0092 (20130101); D06M
17/04 (20130101); D06M 17/10 (20130101); C09J
167/02 (20130101); C08G 18/706 (20130101); D06M
17/08 (20130101); C09J 177/00 (20130101); C08L
2666/08 (20130101); C09J 167/02 (20130101); C08L
2666/08 (20130101); C08L 2666/28 (20130101); D06N
2211/10 (20130101); C08G 2170/20 (20130101); C08L
51/04 (20130101); C08L 9/00 (20130101); D06N
2203/042 (20130101); C08L 2666/08 (20130101); D06N
2205/20 (20130101); C08L 2666/28 (20130101); D06N
2205/06 (20130101) |
Current International
Class: |
C08G
18/79 (20060101); D06M 17/00 (20060101); D06N
7/00 (20060101); C09J 167/00 (20060101); C09J
167/02 (20060101); C08G 18/00 (20060101); D06M
17/04 (20060101); C09J 177/00 (20060101); D06M
17/08 (20060101); D06M 17/10 (20060101); C08G
18/60 (20060101); C08G 18/70 (20060101); C08L
51/04 (20060101); C08L 51/00 (20060101); C08L
9/00 (20060101); C08F 009/10 (); C08L 083/00 ();
B41F 017/00 (); B05D 007/00 () |
Field of
Search: |
;523/211 ;524/837
;525/375 ;427/221 ;101/36 |
References Cited
[Referenced By]
U.S. Patent Documents
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|
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5264515 |
November 1993 |
Cody et al. |
6300413 |
October 2001 |
Simon et al. |
6344238 |
February 2002 |
Schmitt et al. |
6664318 |
December 2003 |
Bymark et al. |
|
Foreign Patent Documents
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198 21 355 A 1 |
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Nov 1999 |
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DE |
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0 940 461 |
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Sep 1999 |
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EP |
|
Primary Examiner: Yoon; Tae H.
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier
& Neustadt, P.C.
Claims
What is claimed is:
1. A microencapsulated adhesive component, comprising: a
cross-linking constituent microencapsulated with a silanized
polybutadiene.
2. The microencapsulated adhesive component as claimed in claim 1,
wherein the cross-linking constituent is micro-encapsulated with a
silanized polybutadiene in a ratio of 4:1.
3. The microencapsulated adhesive component as claimed in claim 1,
wherein the silanized polybutadiene has a silicon content of 2 to
10% by weight, a molecular weight of 1500 to 2500 g/mol and a
viscosity of 1000 to 3000 mPas.
4. The microencapsulated adhesive component as claimed in claim 1,
wherein the cross-linking constituent is an isocyanate compound
which has more than two reactive groups per molecule.
5. The microencapsulated adhesive component as claimed in claim 4,
wherein the isocyanate compound has a melting range of 110 to
130.degree. C.
6. The microencapsulated adhesive component as claimed in claim 1,
wherein the cross-linking constituent is an isocyanate which is
reactive with a second constituent which is a copolyamide or
copolyester.
7. The microencapsulated adhesive component as claimed in claim 6,
wherein the second constituent is an amine-terminated copolyamide
with a melting range of 90 to 150.degree. C. and a solution
viscosity or relative melting viscosity .eta./c in the range of 1.2
to 1.7.
8. The microencapsulated adhesive component as claimed in claim 6,
wherein the second constituent is an OH group terminated
copolyester prepared from terephthalic acid, isophthalic acid and
butanediol or butanediol in combination with small quantities of up
to 12 mole % of another diol, having a melting point of 100 to
150.degree. C.
9. An aqueous printing paste, comprising: the microencapsulated
adhesive component of claim 1 dispersed in an aqueous paste.
10. The printing paste according to claim 9, wherein the paste
further comprises an acid catalyst, a commercial surfactant, a
defoaming agent, a thickener and water.
11. An aqueous adhesive printing paste, comprising: the
microencapsulated adhesive component of claim 1 combined with a
second constituent of a copolyamide or a copolyester dispersed in
an aqueous paste.
12. A process, comprising: micro-encapsulating a cross-linking
constituent in a silanized polybutadiene.
13. The aqueous adhesive printing paste of claim 11, wherein the
cross-linking constituent is an isocyanate compound.
14. The aqueous adhesive printing paste of claim 13, wherein the
second constituent is an amine-terminated copolyamide with a
melting range of 90 to 150.degree. C. and a solution viscosity or
relative melting viscosity .eta./c in the range of 1.2 to 1.7.
15. The aqueous adhesive printing paste of claim 13, wherein the
second constituent is an OH group terminated copolyester prepared
from terephthalic acid, isophthalic acid and butanediol in
combination with small quantities of up to 12 mole % of another
diol, having a melting point of 100 to 150.degree. C.
16. The aqueous printing paste of claim 9, wherein the
cross-linking constituent is an isocyanate.
17. A method comprising applying the aqueous printing paste of
claim 13 to a substrate.
18. The method according to claim 17, wherein the aqueous paste is
applied to a substrate by rotary screen printing.
19. A method of bonding surfaces, comprising: applying the paste of
claim 16 onto a surface as the base dots of double dot technology
as a strike back barrier; applying, as the upper dot component of
the double dot process, an amine terminated copolyamide; and
effecting bonding between the materials of the applied dots.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for manufacturing a
micro-encapsulated cross-linkable hot-melt adhesive coating based
on an aqueous paste comprising a micro-encapsulated polyisocyanate
dispersion and a commercially available amine-terminated
copolyamide or copolyester for the manufacture of a base dot as a
strike back barrier in double dot coating. The upper dot comprises
an amine-regulated copolyamide for ensuring good bonding to the
lower dot. More particularly, the invention relates to a hot-melt
adhesive compound for a grid-like coating of fixable interlining
materials for the garment industry, in particular for
outerwear.
2. Description of the Background
In the interests of solving the problems of reduced washing and dry
cleaning resistance of fabrics, as well as weaker adhesion,
improved hot-melt compounds have been developed, as have improved
coating technologies. Duo dot or double dot coatings are described
in patents DEB 22 14 236, DE-B 22 31 723, DE-B 25 36 911 and DE-B
32 30 579, for example.
The coating carriers were improved according to the state of the
art in that finer yams with fine-denier single fibers including the
microfiber range and synthetic yams such as high bulk acrylic or
polyester yarn are used. The fabrics which were originally used
have been replaced extensively by stitch-bonded fabrics, wherein
the latter materials represent a combination of nonwoven and woven
fabrics. These combinations result in very soft, though very open
structures which place higher demands on coating methods and
hot-melt adhesive compounds, in particular with respect to strike
back and bleed-through of the hot-melt adhesive compound.
Because of costs and quality reasons, there has been a noticeable
drop in the amount of coating applied per m.sup.2 of interlining
material. Whereas previously coating quantities of 15 to 20
g/m.sup.2 were common, nowadays the coating quantities range from 7
to 12 g/m.sup.2.
Despite the small quantities, adequate adhesion and fastness must
be guaranteed, that is, the hot-melt adhesive may not penetrate
into the interlining, otherwise it is no longer available for
actual adhesion.
The investigation leading to the present invention was to find an
effective strike back barrier which exhibits high bonding strength,
good bonding of the upper dot on the base layer and good washing
and dry cleaning resistance, as well as having a sterilizing
capacity, with a reduced quantity of coating material. Another
advantage would be that a higher level of thermal stability under
load is achieved.
The state of the art is such that a range of strike back barriers
is known, such as cross-linking acrylate and polyurethane
dispersions and powder-filled pastes based on high-melting
copolyamides and polyethylene and high-viscosity thermoplastic
polyurethane powders. All of these systems have more or less major
disadvantages when applied to rough, napped interlinings and in
their bonding to the upper dot or in their wash-resistance.
In the case of coatings of self-cross-linking acrylate or
polyurethane dispersions, partial cross-linking frequently occurs
during coating, which may result in a coating forming on the
template and thus blockage of the template holes. Extensive
cleaning of the plant is then required. When production-related
downtime occurs, the downtime can also cause major difficulties and
disturbances to the point that the templates become unusable. Also,
when the material is being applied, bonding of the upper dot to the
base layer is a problem. The high-viscosity powder-filled systems
based on polyamide, polyethylene and polyurethane generally do not
satisfy the resistance to strike back that is required.
To date there has been no success in creating a stable cross-linked
system for the base dot. The isocyanates preferably used for this
purpose were unable to be stabilized against water (matrix for
coating pastes) or the activation temperatures required for
crosslinking (greater than 150.degree. C.) were excessive.
For special applications where the activation temperature can be
higher (>150.degree. C.), for example, for fixing shirt collars,
internally blocked polyisocyanates, e.g. dimerized polyisocyanates,
may be employed. Powder mixtures of this polyisocyanate and the
amine-terminated copolyamide or copolyester can also be processed
by means of other application techniques such as by powder
dispersion or powder dot. At the present time, polyethylene with
melting points of 110.degree. C. to 120.degree. C. or
higher-melting polyamides in the melting range of 130.degree. C. to
160.degree. C. have been used for fixing shirt collars.
Isocyanates have had to be stabilized against water or against
diffusion of humidity to ensure activability at relatively low
temperatures.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide an
effective strike back barrier which exhibits high bonding strength,
good bonding of the upper dot on the base layer even on rough bases
and good washing and dry cleaning resistance, as well as a
sterilizing capacity with a reduced quantity of coating
material.
Another object is to achieve increased thermal stability under load
for the hot-melt adhesive coating and to facilitate processing of
the dispersions, as well as preventing the templates from becoming
blocked.
Still another object of the invention is to clearly improve the
sensitivity of the isocyanate to humidity.
Briefly, these objects and other objects of the present invention
as hereinafter will become more readily apparent can be attained by
a process comprising micro-encapsulating a cross-linking
constituent with a silanized polybutadiene, the reactive
constituents of the cross-linking constituent has been first
reacted in the melt with cross-linking, thereby manufacturing a
cross-linkable hot-melt adhesive compound for coating and/or
laminating surface formations.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Silanized polybutadiene, which forms stable and water-impermeable
capsules on contact with water or moist steam atmospheres, is
suitable as a capsule material. It is known that silanized
polybutadienes may be employed for micro-encapsulation, but their
applicability in conjunction with isocyanates and amines was
surprising. It would have been assumed that isocyanate or amine and
silane react with one another so that the isocyanate which
generates the hot-melt adhesive is deactivated or destroyed and is
no longer available for hot-melt adhesive formation for the
intended use. It would also have been assumed that isocyanate and
the moist medium required for cross-linking or generating the
capsule structure of the silanized polybutadiene in situ is
damaging to the isocyanate in that it immediately hydrolyzes.
However, the objective of the present invention has now been
reached with an isocyanate, having more than 2 free NCO groups and
a melting range of 110 to 130.degree. C., e.g., trimerized
polyisocyanate products, which in micro-encapsulated form, are
employed in a paste formulation.
The surprise of the present invention is that isocyanates are very
sluggish in reaction vis-a-vis the silane and that microcapsules
can be formed. In addition to this, micro-encapsulation obviously
occurs so rapidly that hydrolysis of the isocyanate is entirely
prevented and moisture, which might damage the isocyanate, is
prevented from penetrating into the microcapsule.
The micro-encapsulated isocyanates are manufactured by mixing the
isocyanate constituent with the silanized polybutadiene. The mixing
temperature is adjusted to the melting points of the mixed
materials and as a rule ranges from 100.degree. C. to 150.degree.
C. The cross-linking constituent and the silanized polybutadiene,
in a ratio of 4:2 to 4:1, preferably 4:1, are charged into a
reactor. The polybutadiene should exhibit a silicon content of 2 to
10% by weight, a molecular weight of 1500 to 2500 g/mol, a
viscosity of 1000 to 3000 mPas and a solids content of greater than
60%. The mixing procedure is conducted under high shear. Also added
to the mixture are approximately 0.5 to 1.5% of a commercial
surfactant, e.g. Intrasol, 0.05 to 0.1% of an acid catalyst, e.g.,
toluenesulfonic acid and 1.5 to 5% of a thickener, e.g., acrylic
acid ester thickener and other additives, if required.
A characteristic of the cross-linkable hot-melt adhesive compound
of the present invention for the coating and/or laminating of
surface formations is that the reactive constituents present in the
hot-melt adhesive compound first react, with cross-linking, in the
melt. The crosslinking constituent is added to the coating paste in
the form of a micro-encapsulated polyisocyanate dispersion. In this
preferred initial form, a commercial copolyamide with amino end
groups and a trimerized diisocyanate, which has been rendered
nonsensitive to water, is processed into a paste. The material to
be processed is then coated by means of rotary screen-printing. A
copolyester may be used in place of the copolyamide. A preferred
embodiment of such is an OH group terminated copolyester based on
terephthalic acid, isophthalic acid and butanediol or butanediol in
combination with small quantities of up to 12 mole %, preferably
from 6 to 10 mole %, of other diols such as, for example,
hexanediol or polyethylene glycol, having melting points of 100 to
150.degree. C. During subsequent drying in an oven at approximately
120.degree. C. results in cross-linking within a few seconds, and a
cross-linked strike back barrier for the double dot is obtained. In
this way the usual problems of systems containing isocyanate can be
circumvented. By way of example, other systems require blocked
isocyanates, where the likes of caprolactam or oximes are used as
blocking agents, and require excessively high activation
temperatures. Another advantage of the present invention is that no
low-boiling inflammable solvents are released during fixing, since
an aqueous suspension is present.
Having now generally described this invention, a further
understanding can be obtained by reference to certain specific
examples which are provided herein for purposes of illustration
only and are not intended to be limiting unless otherwise
specified.
EXAMPLE 1
A 160 g amount of 70% polyisocyanate solution of trimerized IPDI
are mixed together with 40 g of a silanized polybutadiene having a
molecular weight of 1500 to 2500, a viscosity of 1000 to 3000 mPas
and a solids content>60%. The result is a clear homogenous
mixture. This mixture is added slowly to an aqueous solution
comprising 500 g water, 10 g Intrasol, 0.5 g p-toluenesulfonic
acid, 1 g defoaming agent and 30 g of a commercial aqueous
thickener under high shear by means of a stirring apparatus which
generates high shear forces (Ultra Thurrax). Under hydrolysis
conditions the capsule-forming material immediately encapsulates
the polyisocyanate by forming a waterproof shell that can be
destroyed or released by pressure or heat upon the intended
use.
The dispersion or the print paste prepared in this manner now has
particularly advantageous properties:
The paste, which is printed as a base dot (strike back barrier) for
the so-called double dot, cross-links during drying in the attached
hot-air duct and melts with the scattered amine terminated
copolyamide (upper dot). Bonding is particularly good because the
amino end groups from the upper dot, at the boundary surface to the
base dot, react with the cross-linking constituent, resulting in a
fluent transition from the cross-linked base layer to the
thermoplastic upper dot which guarantees actual adhesion.
To attain particularly good bonding of the upper dot onto the base
dot, it is advisable to use an amine-regulated copolyamide as the
upper dot material. Appropriate products for the base and upper dot
are low-viscosity, low-melting grades. The melting point should
range from 90 to 150.degree. C., preferably from 115 to 130.degree.
C., with a solution viscosity in the range of 1.2 to 1.7 mPas,
preferably 1.25 to 1.4 mPas. The boundary layer thereby reacts with
the isocyanate paste and creates a very resistant connection of
both dots. The coating quantities for the base dot should be 2 to 5
g/m.sup.2, preferably 2.5 to 4 g/m.sup.2, and for the upper dot the
coating quantities should be 4 to 8 g/m.sup.2, particularly 5 to 7
g/m.sup.2. The base dot can be applied grid-like as a paste.
Internally blocked polyisocyanates, e.g., dimerized polyisocyanate,
can also be processed without being encapsulated in paste because
they are not susceptible to water. The use of such systems is
limited to a temperature range above 150.degree. C., for example
for shirt collars, because the textiles being used here, generally
cotton, tolerate higher temperatures. A paste formula, VESTAMELT X
1316-P 1 (Degussa Huels), is suitable as a hot-melt adhesive.
EXAMPLE 2
An amine-terminated copolyamide of Degussa-Huels AG (VESTAMELT X
1027-P 1) and an encapsulated polyisocyanate dispersion
manufactured in the above-mentioned manner were processed into a
printable paste with commercially available dispersing agents and
thickeners, e.g., Intrasol 12/18/5 and Mirox TX marketed by
Stockhausen, and as described in DE-B 20 07 971, DE-B 22 29 308,
DE-B 24 07 505 and DE-B 25 07 504, and printed using a rotary
screen printer with a CP 66 template on a 35 g polyester fabric
with high bulk yarn. The coating was 2 g/m.sup.2. VESTAMELT X
1027-P816 was scattered on the still wet paste dot, the excess was
suctioned up and the article was dried and sintered in a drying
oven at 130.degree. C. The upper dot had a coating of 5 g/m.sup.2,
making the total weight 7 g/m.sup.2.
Paste Formulation of the Base Dot:
1500 g Water
35 g Mirox TX (polyacrylic acid derivative)
40 g Intrasol 12/18/5 (ethoxylated fatty alcohol)
200 g polyisocyanate dispersion (approx. 5% trimerized IPDI) from
Example 1
600 g VESTAMELT X 1027-P1
The amine-terminated VESTAMELT X 1027-P816 of Degussa-Huels AG was
scattered as a scattering material.
Result:
A 5 cm wide strip of this interlining was fixed to a siliconized
blouse material from a cotton/polyester mix at a bonding
temperature of 127.degree. C. for 10 s and a linear pressure of 4
N, after which the composite was subjected to a 60.degree. C.
wash.
Primary adhesion: 16 N/5 cm
60.degree. C. wash: 14 N/5 cm
Back riveting: 0.1 N/10 cm
On Example 11: (Comparison to the State of the Art)
A paste system based on copolyamide polyethylene was applied to the
same interlining base and scattered with the same upper dot
material, then dried and sintered. The same quantities of base dot
and upper dot were applied.
Paste Formulation:
1500 g Water
35 g Mirox TX
40 g Intrasol 12/18/5
400 g SCHAETTIFIX 1820 (high-density polyethylene)
200 g VESTAMELTX751-P1
The SCHAETTIFIX 1820 is a high-density polyethylene with a melting
point of 128 to 130.degree. C. and a melt index of 20 g/10 min.
Result:
Primary adhesion: 9 N/5 cm
60.degree. C. wash: 5 N/5 cm
Back riveting: 0.9 N/10 cm
The advantage of the process of the present invention is that,
under the drying conditions, the lower dot already cross-links and
during melting the upper dot cross-links because of its termination
with the lower dot, thereby creating an optimum bond. Since after
coating the molecular weight of the lower dot is increased
strongly, it can no longer sink into the fabric. During the
subsequent fixing process, the low-viscosity polyamide of the upper
dot is forced to flow against the material to be fixed, since it
cannot flow downwards; a very high degree of adhesion is
consequently attained with minimal quantities of hot-melt adhesive.
The separation layer, previously the weak point of the system,
particularly during washing, between upper dot and base dot cannot
be attacked so strongly hydrolytically as is the case with
previously known systems and it accordingly exhibits substantially
higher resistance.
Products Used:
VESTAMELT X 1027-P1 is a ternary copolyamide of Degussa-Huels AG
based on LL, CL and DDS/MPD with amino end groups, melting point of
120.degree. C., amino end groups 100 to 400 mVal/kg, preferably 250
to 350 mVal/kg.
The trimerized isocyanate is a polyisocyanate with a functionality
of 3 to 4 and with a melting point of 100 to 115.degree. C. It is a
product of Degussa-Huels AG.
EXAMPLE 3
1500 g Water
35 g Mirox TX
40 g Intrasol 12/18/5
400 g VESTAMELT X 1316-P1
200 g VESTAMELT X 1310-P1
Result:
A 5 cm wide strip of this interlining (75 g/m.sup.2 cotton) with a
CP 66 screen and a coating of 16 g/m.sup.2 was fixed to a
siliconized blouse material from a cotton/polyester mix at a
bonding temperature of 155.degree. C. for 16 s and a linear
pressure of 4 kg/cm.sup.2, on a shirt press, after which the
composite was subjected to a 60.degree. C. wash.
Adhesion: 21 N/5 cm
60.degree. C. wash: 19 N/5 cm
Test 3a: (Comparison to State of the Art)
As in Test 3, 16 g/m.sup.2 of a commercially available coating was
applied to the same interlining, as per the following
formulation:
1500 g Water
35 g Mirox TX
40 g Intrasol 12/18/5
600 g VESTAMELT X 250-P1
The Following Adhesions Resulted Under the Same Fixing
Conditions:
Primary adhesion: 16 N/5 cm
60.degree. C. wash: 5 N/5 cm
Result:
Hydrolysis resistance is sharply increased by cross-linking
(molecular weight increase), something that becomes clearly
noticeable in the wash resistance. The strike back inclination is
strongly decreased by the gradual molecular weight increase during
fixing, effectively increasing adhesion.
The disclosure of German priority application Serial No. 10050231.8
filed Oct. 11, 2000 is hereby incorporated by reference into the
present application.
Obviously, numerous modifications and variations of the present
invention are possible in light of the above teachings. It is
therefore to be understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described herein.
* * * * *